System for protecting a main shaft of an engine having a fusible bearing

Abstract

A turbomachine comprising at least a first rotary assembly with a first shaft, a stator, and bearings secured to the stator and suitable for supporting the shaft, one of the bearings being capable of giving way when an unbalance occurs in the rotary assembly, at least one segment of the shaft being covered in a covering which comprises at least one piece of fabric impregnated with resin and which is for coming into contact with a surrounding portion of the turbomachine when the unbalance occurs in order to protect the first shaft and ensure that there is no risk of the first shaft rupturing. The turbomachine is intended to be used mainly in the field of aviation, and more particularly as an airplane turbojet.

1. A turbomachine comprising at least a first rotary assembly with a first shaft, a stator, and bearings secured to the stator and suitable for supporting said shaft, one of said bearings being capable of giving way when an unbalance occurs in the rotary assembly, wherein at least one segment of said shaft is covered in a covering which comprises at least one piece of fabric impregnated with resin and which is for coming into contact with a surrounding portion of the turbomachine when said unbalance occurs. 
   
   
     2. A turbomachine according to  claim 1 , wherein said piece of fabric is made of braided fibers and is wound around said segment. 
   
   
     3. A turbomachine according to  claim 1 , wherein said piece of fabric is formed by a sleeve of fibers capable of being slid onto the first shaft. 
   
   
     4. A turbomachine according to  claim 3 , wherein, when the shaft segment is situated between two adjacent shaft portions of outside diameter greater than the outside diameter of the segment, said sleeve is deformable. 
   
   
     5. A turbomachine according to  claim 4 , wherein the covering includes a plurality of sleeves of superposed fibers. 
   
   
     6. A turbomachine according to  claim 2 , wherein the fibers are selected from the following reinforcement fibers: carbon fibers, aramid fibers, and glass fibers. 
   
   
     7. A turbomachine according to  claim 1 , wherein the resin is selected from the following resins: epoxy resins, bismaleimide resins, and phenolic resins. 
   
   
     8. A turbomachine according to  claim 1 , wherein the resin contains dry lubricants so that the coefficient of friction between said covering and the surrounding portion of the turbomachine is reduced. 
   
   
     9. A turbomachine according to  claim 1 , wherein a first intermediate layer is disposed between the shaft segment and the covering, and is such that the coefficient of friction between said intermediate layer and the surrounding portion of the turbomachine is greater than the coefficient of friction existing between the covering and said surrounding portion. 
   
   
     10. A turbomachine according to  claim 1 , wherein a second intermediate layer is disposed between the shaft segment and the covering or between the shaft segment and the first intermediate layer, said second intermediate layer serving to prevent a galvanic-corrosion phenomenon from becoming established between the first shaft and the covering or the first intermediate layer. 
   
   
     11. A turbomachine according to  claim 1 , further comprising a second rotary assembly with a second shaft, the first and second shafts being coaxial and capable of rotating at different speeds, and wherein said surrounding portion belongs to the second shaft of the turbomachine. 
   
   
     12. A turbomachine according to  claim 1 , wherein said surrounding portion belongs to the stator of the turbomachine. 
   
   
     13. A turbomachine according to  claim 1 , wherein the turbomachine is an aeroengine.